Control apparatus



Dec. 15, 1953 Filed Feb. 18, 1950 AIR SUPPLY F. H. FELLOWS ETAL CONTROLAPPARATUS 2 Sheets-Sheet l INVENTORS AND FRANK H. FELLOWS By HARVARD H.GORRIE 5 9 F. H. FELLOWS ET AL 2,662,509

CONTROL APPARATUS Filed Feb. 18, 1950 2 Sheets-Sheet 2 INVENTORS FRANKH. FELLOWS FIG. 2 AND HARVARD H. GORRIE Patented Dec. 15, 1953 a UNITEDSTATES Frank H. Eellows; (llevela nd anii 7' Gdir cl v aiidfl ie 1 5 QBailey Me't'e'r Company, acofpoiatiofldf e13 ware Application February18, 1930, Serial No. 145,032

i'ti'ciaiih's. (01.122451) Safety devices inthecontrofl power 0;:automati Producing m h rengm h itea il n' u q t e portance as theequipment of modern; power plants continues to represent largercapitalexfor maintaining d water supply control in a penditures. Warningdevices are needed to in- 6 vapor g en rator gn ggntinnousoperationdespite form operators of the development of critical thefailu're of theprimary control system of said conditions at multiple stations inthepower pro supply. I a M I ducing equipment. In addition to' signals,bells and alarms, there is a need for devices to monitor W thefunctioning of normally: operative automatic Q Q P d ,W% Q controlsystems and, upon the failure of motivat- ,991 $34 M? the 0 pron failureof a primary e mluto nct naQfie, 5f? m entioni to provide means we wishto provide means for f thermohydraulic systo a feed Waterv valve pnairsupply to a multiing power to a control system as a unit, means ga ieieiwat r'qq2191 are needed which either immobilize the units Fi a c emeiqi l t at p Q e normal responsive to such systems r which shift aporica n l pri ary s stem p feed, water tion, or all, of the fun tion ofthe primary sys- 15 QQ WFQ WI P F F PFQSFWJI YQPWQ positiqnevd in tem tosecondary systems maintained in oper- D1 91 'eltr lqili f i @QQQ te valvfor applyability for just such eventuality: esthevcqn qleiieqt r aeconda y y o Aside from purely economic reasons, marine eti W FQQQQWQW .teieedwat r Valve power installations have theneedof secondary 11129 a uo he pqw r s p y o the primary control systems Which can function'in theevent Y i; i of primary control system failure to maintain F 7 g .1 emQdlm the operation of vessels at'a-practical level of i their efiiciencyunder h a zards of military operanf- 9 9 2 t P inclusion of a handtions.The largest, unified-factor in the eifectivei ior' anualp, .1 ins-,

. t 11355 of a ma -jne yes sel is jts power pfoducjng ig. 3 iS amodification Of the embodiment Of our invention illusstandardvalvehousing ability, and the most important system in the i,., r' functionof its power producer isthatof the con-'5 Pl; E- 1 1?;- y5 1 .Qf ewatffr trols of the comhustionprocess whose heat is 9 ol EJ1 d as reiqre tat e a maintained in transfer relationship to, the vapor m y"s'stemarranged with a vapor generator i generator, or boiler, and thcontr olof the supply 30 the-Ma n r peeesser w na giall o p its of vaporizableliquid tosuc h section 'P i 1 9, 9? fil er oontrol valve If theindividual units of-theautomatic system Q lym ,9 sae tialsn, conv ntinal ystem are powered by air pressure-a failure ofsuch sup .l e qr r peter, are showntq p i the ply produces the aforementioned critical needbi1S/QP,;E ;,Q -I P ,3? 9 .9? tiQ which must be met by iniariiialsupervision of,,or C9 q1 1$ l fl mllqq li liql Y R- Y l S h somesecondary means of automatically position- 31 9 5 1 rolthe flowofvaporizing, the vital units which cannot with, safety be able liqu ri 4apor generator-section immobilized for any substantial length of time.5, toyhichheat is app by ineansnot shown,

If practically all units, such as draft dampers, to p rpduce vaporflowing therefrom through a fuel feeders and em; a mmob l eea it..:iianyparticular point of a normal period of op r gr A primary element 2, suchas an orifice, is iniion the power prmiud'will re e n .2 asa teqliaecnst e the vap r fl w gald although its e en i 'i l fi let etea mwerllfliq eei y P9 91mi d i sni al re s re epredeinand changes, with nofundamental damage sentative of the re ,qf yaporgenerated within likelyto Occur d b' i ,ele i sa .QY v i lfi.zagqli ilmg rl hfillei lqmthrou,.C0n 1 t l-lowever, igne- I 3, j l jhe continuously determineddifferential is na-ibezsunnl gi enu ili of vaporizable liquid to thegenerator section will; :11 :te device. Q A

with relative rapidity, eitherjempt'y that section' to modify the a ofliquid or overflow thefgener'ator and flood the vapor-operatedapparatus. i v I A Therefore, it isnecssaryfthat soniedegree of responseto change'in the mountofliquidin In 11' generating sectionbe'ma'intainedu'ndr even the most extreme conditions forleinerg encyoperatherewith pgsitions v To meet 5115B -f yi q lpi'e pn has a toicontinuwsivmo m s l to nasits object the applibatioii of a, secondarysystem ren'i tebisur within conduit 8. The pressures within conduits 6and 8 are then conducted to air supplied relay H by means of which athird pressure is established in conduit 12 for transmission to valvepositioner 13, which may take the form of the subject matter ofcopending application Serial No. 47,516 of Gorrie et al., forpositioning feed water control valve 1.

The power supply needed for operation oi. pilot valves 1 and 9, therelay II, and valve position- 'er I3, originates from a common source ofair supply. It is emphasized that a power supply of air is used in thepresent instance only as an illustration in explanation of the functionof the embodiments of our invention,and it is easily con-' ceivable thatother mediums of activation may be employed with our invention. 1 i

To continue with an explanation of Fig. 1, a representative selection ofthe common air supply is introduced, by means of conduit l4, into pistonhousing 15 that its pressure may be conventionally effective upon theface of piston Hi, to move it against the force of spring 11 andcompress said spring between piston l6 and plate 18. The housing l andthe piston 16 comprise an expansible chamber with a movable wall. Plate18 has an opening for piston stem l9 which may have a bushing formaintaining alignment of said piston therethrough from attachment withpiston it within the housing l5. Plate l8, and/or its bushing, maintainspring l1 in compression with piston l6. Housing is secured firmly tothe housing of valve l to maintain piston stem 19 therein in asubstantially vertical position.

4 the period of non-operative engagement, stem 26 is driven throughmember 20 until a limiting shoulder on said stem engages lever member20.

During operation of the primary system of feed water control, that is,while the control pressures in conduits 6 and 8 are producing pressureswithin conduit [2 to control the position of feed water control valve 1through the action of valve positioner 13, the common source of airsupply pressure maintains piston l6 against the force of spring 11, toan elevation such that complete disengagement of stem members 26 and 21is maintained. During the period, the secondary system of control,illustrated by the thermohydraulic system at 29, maintains its controlpressures in conduit 28 and bellows 25, driving stem member 26 downwardthrough its hole in lever member 20 until the limiting shoulder orprotuberance on said stem engages upon member 20, limiting the expansionof bellows and preventing engagement of stem member 21 with stem member26.

Upon failure of the common source of air power supply to the primarysystem of control, the

decay of the pressure of the air supply, transmitted by conduit M to amonitor device including housing 15, allows the force of spring I"! todrive Y piston It to the bottom limit of its housing 15.

Lever 20 rotates about a pivot 2| in accordance with the verticalmovement of piston stem 19 attached to the opposite end thereof. Asreciprocation of piston member I5 is desirably maintained with verticalmovement of stem member 7 19, the necessary cooperation by said stemwith the rotation of member 20 about pivot 21 is had through a slot 22.Also provision is made on member 20 between pivot 2land slot 22, forsecuring thereto a bellowshousing 24 into which are conducted pressuresfrom a secondary system of feed water control. Pivot 2| is given a fixedposition by reason of rigid bracket member 23 being secured firmly tothe diaphragm housing of valve I.

The bellows housing 24 contains an expansible chamber in'the form of abellows 25 in order to subject said bellows to the control pressuresfrom a secondary system for feed water control, represented bythermo-hydraulic control system 28. In arrangement of this controlapplicator or monitor with bellows 25, a stem member 25 is provided toextend through lever member 20 at the point that rotation of said leverwill operatively engage, or disengage, the stem member 26 and stemmember 21 of feed water control valve 1.

Stem member 21 is the conventional means by which the ports of fluidcontrol valve l are positioned. From its attachment to the closure meansfor said ports, stem member 21 extends up through a framework supportingwhatever means are used to control stem position. The length of stem 21may be varied, depending upon the application, in the present instance,the length necessary to extend it above the bellows housing foroperative engagement with stem member 26.

Bellows stem 26 is arranged with bellows 25 that its vertical positionwill reflect control pressures transmitted to bellows 25 upon stem 21during the period of operative engagement. During This downward movementof piston l6 causes stem 19 to rotate lever 20 counterclockwise aboutpoint 2! until engagement between stem 26 and 21 becomes operative, andthe rotation continues the degree suihcient to disengage the shoulder ofstem 28 from its contact with lever member 20 in order that thesecondary system control pressures in conduit 28 will be transmitted byway of bellows 25 and stem 26, their values positioning stem 21 or" feedwater control valve I in opposition to the standard spring member of thevalve which tends to move stem 21 in an upward direction. Specificsizing of bellows 25, housing 24, stem 26, stem 19, spring I1 and piston16 have been deliberatelyavoided as falling within the realm of designconsiderations, the force needed for positioning valve stem 21, and themovement needed for complete disengagement of stems 2B and 21 duringnormal function of the air supply.

Handjacks are commonly utilized to override any automatic control effecton control valves during periods when manual positioning is desirable orrequired. Handjacks may assume the form illustrated in Fig. 2 whereinthe control, hand wheel is designated 34. Rotation of 34 raises orlowers the attached stem ZFA by reason of thread engagement withdiaphragm housing 35. The vertical movement is transmitted acrossdiaphragm 36 to plate 31, resting upon spring cage 38 retaining aconventional valve spring 39 which tends to move cage 38 upward byreason of the force of compression and therefore attached valve stem21A. Valve stem 21A. extends from engagement with the handjack anddiaphragm 36 down into body 40 of the control valve lA to position thevalve discs 41 in desired relation to the seats of valve cage '42 forregulation of the flow rate of fluid through-the'body 40. Continuouscontrol of valve stem 21A of Fig. 2, or 21 of Fig. 1, is the specificobject of our invention, and the two embodiments of these figuresillustrate its flexibility in event of the desirability to includeauxiliary equipment, as the handjack, to the diaphragm housing whichmight interfere with the operation.

Take initial note, in connection with examination of Fig. 2, of membersgiven an A followanalogous to those complementary members designated inFig. i without an A following as torender such technique advantageous incorrelating the similar operation of the embodiments.

In the embodiment of Fig. 2, bellows housing 24A is supported by abracket 43- from the frameof control valve I A- in a position from whichits stein 26A can extend through said" bracket and attach tolever member20A through a pivot at 44 Lever member 20A- carriesa roller- 45 tooperatively engage valve stem 21A by bearing uponco1lar-46 attached to21A;

Thus it can beeasily analyzed, that during normal operation, thecommonairsupplypres-- sure drives piston ISA upward tocompress springI-1=A- and rotate lever 29A clockwise about pivot M until disengagementof members 45 and 46 is complete. Secondary-control pressure in conduit28A- expands bellows within housing 24A until a shoulder of stem' 26Apositively engages plate member l3, giving a fixity of position to pivot4* when lever member 20A rotates thereabout during disengagement.

Upon failure of the common air supply, the decay of its pressure inconduit MA allows spring I'IA to drive piston ISA downward and rotatelever member 26A about pivot 44- by means of attached piston stem ISAthrough a slot at 22A. During thiscounterclockwise rotation, operativeengagement between roller45'and collar 46 oocurs,;andthe rotationcontinues the degree sufiicient to raise the limiting shoulder onbellows ste n 26A from its engagement with bracket member-43 thatthesecondary control elfect may be given transmission to valve stem- 21Athroughsubsequent rotation of lever member 20A about position" 2213;.

Provision is made tominimize shock on the apparatus, and the secondarysystem of control it applies, through a restriction in the conduit ofcommon air supply line 14A- entering housings I and I 5A of- Figs. landz'r'esp'ectively. With the restriction, or orifice, properly sized, thedec'aying of the pressure of the common air supply is limited-to amaximum rateand the apparatus of the invention isbroughtinto operationslowly enough to allow the secondary'system of control to make the minorself-adjustments it might require to-smoothly assume-control ofthervalve I. Referring now to Fig. 3, thereis shown a modification ofthe Fig. 1 embodiment of our invention' which is feasible if broaderlimits of liquid level indrum 5 are permissible.

It may easily be the case that the limits of the level to which thevaporizableliquid within generator 5 ,must be held may'vary beyond thosemaintained by the primary system of control. If that variation ispermissive; the secondary system orcontrol may-be calibrated to hold theliquid level lower than the level held by the primary controlsystem andreduction of level due tofailure of'the primary system and the closingof valve I under influence of its spring will be checked'by theassumption of: control by the secondary system at the lower'level.

It is obviousthat primary control system failure must: always, allow thevalve spring of I to close the valve ports so that the level will sinkin drum 5. And it is further obvious that the secondary controlsystemmust'be set at a level enough belownormal that itwill produce nocontrol eirect during that normal period which will interfere with thepositioning-of valve stem" 21 by theprimary control system:

iunction desired is disclosed by Fig; 3. Conduit 28, bellows 25, housing2-4and stem 26 cooperate in the same manner as in the Fig. 1 embodiment.However, housing 24' is firmly attached to plate 26B which holds stem26- in vertical alignment with valve stem 2? by virtue of its rigidattachment to the housing of valve I by means of brackets 23 and 54).All that remains is to calibrate both primary and secondary controlsystems that normal positions taken by stem 21 under influence of theprimary control system will not cause stem- 26 totransmit controlpressures from the secondary control system thereto of a magnitude thatthe-normal-operation will be biased undesirably. Then failure in theprimary system will cause valvestem 2"! to rise under valve springpressure until stem 26 i's transmittin control pressures of thesecondary system as it senses the sinking-level of the liquid withindrum 5.

If this standard of operationis satisfactory'for a particular system,the Fig. 3 embodiment of our invention will obviously eliminate manymoving parts of the prior embodiments with consequent reduction in wearof parts andcomplexity of design.

We have illustrated one form that our invention may assume inpractice-with anair supplied, primary system of feed'water control; anda hydraulic operated secondary system of feed water control, but wedesire in no wiseto be limited thereto. Our invention is conceivablyadapted to many forms of primary and'secondary control systemsfunctioning with various mediums of power.

What we claim as new and desire to secureby Letters Patent of theUnitedst'ates, is:

1. A control system for regulating the supply of an agent to vary ormaintain a condition, including in combination; means responsive to afirst operating variable of the condition, a primary source of fluidpressure to said means, said primary fluid pressure varied in accordancewith said operating variable by said-responsive means, a first controlmeans sensitive to the variation of the primary fluid pressure,regulating means for controlling the supply of an agent, said'firstcontrol means operable to control said regulating means, said firstcontrol means operative only in accordance with the variationof theprimary fluid pressure, means responsive to a second operating variableof the condition, a secondary source of fluid pressure associatedwithsaid lastnamed means, said secondary fluid pressure varied inaccordance with said second'operating tion to vary said primary-fluidpressure, said first control means operable to position theadjustablemeans regulating the agent supply, a secondary source of fluid'pressuretobe varied, a second control means sensitive to 3 the variation of thesecondary fluid pressure, a second means responsive to a secondoperating variable of the condition to vary said secondary fluidpressure, and means operative upon the failure of the primary source offluid pressure to actuate the adjustable means for controlling thesupply of the agent through the second control means only.

3, In combination, a multi-element control system actuated in accordancewith an operating condition of a steam generator, a source of airpressure for said system, a first air loading pressure established bysaid multi-element system, a fluid pressure relay responsive to saidfirst air loading pressure, a valve means controlling the supply of feedwater to the steam generator positioned in accordance with the first airloading pressure, a thermo-hydraulic generator control system includinga bellows responsive to the fluid pressure of the thermohydraulicgenerator control system, a housing for said bellows rigidly attached tothe feedwater valve, and means for transmitting the bellows movement tothe stem of said feedwater valve only during periods of air pressurefailure in the multi-element control system.

4. The combination of claim 2 in which the means operative upon thefailure of the primary source of fluid pressure to actuate theadjustable means for controlling the supply of the agent through thesecond control means only includes a monitor device responsive to theprimary source of fluid pressure, means for continuously imposing theeflects of variations of the secondary fluid pressure on said monitordevice, means for maintaining said monitor device in predeterminedrelationship of position to the adjustable means regulating the agentsupply, and means for causing said monitor device to assume anotherrelative position in relation to said adjustable means regulating theagent supply upon decay of said primary source of fluid pressure.

5. The combination of claim 2 in which the means operative upon thefailure of the primary source of fluid pressure to actuate theadjustable means for controlling the supply of the agent through thesecond control means only includes an expansible chamber with a movablewall, means for continuously applying the secondary source of fluidpressure to said expansible chamber, a piston member, means forcontinuously applying the primary source of fluid pressure to saidpiston member, means controlled by said piston member for maintainingsaid expansible chamber in non-operable relation to the adjustable meansregulating the agent supply during application of the primary source offluid pressure to said piston member, and means for maintaining saidexpansible chamber in operable relation to said adjustable meansregulating the agent supply during decay of pressure in said primarysource of fluid pressure.

6. The combination of claim 2 in which the means operative upon thefailure of the primary source of fluid pressure to actuate theadjustable means for controlling the supply of the agent through thesecond control means only includes a casing continuously receiving fluidpressure from the secondary source of fluid pressure, a bellows withinsaid casing upon which said lastmentioned fluid pressure is effective, alever member positioning said casing, said adjustable means including avalve means having an operating stem, means for maintaining a fixedrelation between said lever member and said valve means, and means forpivoting said lever member in direction and extent necessary to bringsaid bellows into operating engagement with the operating stem of saidvalve means upon failure of the primary source of fluid pressure.

'7.The combination of claim 6 in which the means for pivoting the levermember comprises a conduit from said primary source of fluid pressure, acasing connected with said conduit, a piston operable within said casingby fluid pressure from said conduit, a coil spring on the side of saidpiston opposite that acted on by the fluid pressure, a plate membersealing the end of said chamber on the spring side of said piston, and apiston stem member extending through the coil of said spring and throughsaid plate member and connected with said lever member.

8. The combination of claim 2 in which said adjustable means includes avalve member having an operating stem and in which the means operativeupon the failure of the primary source of fluid pressure to actuate theadjustable means for controlling the supply of the agent through thesecond control means only includes a first expansible chamber secured tothe valve means and receiving fluid pressure from said secondary sourceof fluid pressure, a second expansible chamber secured to the valvemeans and receiving fluid pressure from said primary source of fluidpressure, a beam positionable from each end by the expansible chambers,and a fulcrum means attached to the beam adapted to bear upon theoperating stem of the valve means upon failure of said primary source offluid pressure so that the operating stem will be positioned by saidsecondary source of fluid pressure through the first expansible chamberpositioning the beam.

9. The combination of claim 2 in which the means operative upon thefailure of the primary source of fluid pressure to actuate theadjustable means for controlling the supply of the agent through thesecond control means only includes a control applicator having a stemmember responsive to said secondary source of fluid pressure, saidadjustable means including a valve means having an operating stem, levermeans positioning said stem member in relation to the valve means, meansof securing said lever to said valve means at a pivotal point, and meansfor rotating said lever about said point in a direction determined bythe absence or presence of pressure from said primary source of fluidpressure to operatively engage or non-operatively disengage theoperating stem of said valve means with said stem member.

10. The combination of claim 2 in which the means operative upon failureof the primary source of fluid pressure to actuate the adjustable meansfor controlling the supply of the agent through the second control meansonly includes a monitor device responsive to the secondary source offluid pressure, and means for maintaining the monitor device in aposition from which it can apply the effect of variations in thesecondary source of fluid pressure to said adjustable means regulatingthe agent supply upon failure of the primary source of fluid pressure.

UNITED STATES PATENTS Name Date Stewart June 25, 1935 Number

